diff --git a/middleman-cli/lib/middleman-cli/console.rb b/middleman-cli/lib/middleman-cli/console.rb
index 51ddb28e..829e9901 100644
--- a/middleman-cli/lib/middleman-cli/console.rb
+++ b/middleman-cli/lib/middleman-cli/console.rb
@@ -29,12 +29,17 @@ module Middleman::Cli
         ::Middleman::Logger.singleton(opts[:debug] ? 0 : 1, opts[:instrumenting] || false)
       end
 
-      # TODO: get file watcher / reload! working in console
+      interact_with @app
+    end
 
+    # Start an interactive console in the context of the provided object.
+    # @param [Object] context
+    # @return [void]
+    def interact_with(context)
       IRB.setup nil
       IRB.conf[:MAIN_CONTEXT] = IRB::Irb.new.context
       require 'irb/ext/multi-irb'
-      IRB.irb nil, @app
+      IRB.irb nil, context
     end
 
     # Add to CLI
diff --git a/middleman-cli/lib/middleman-cli/server.rb b/middleman-cli/lib/middleman-cli/server.rb
index 47ec23d5..75a8cbfa 100644
--- a/middleman-cli/lib/middleman-cli/server.rb
+++ b/middleman-cli/lib/middleman-cli/server.rb
@@ -11,11 +11,9 @@ module Middleman::Cli
     class_option :host,
                  type: :string,
                  aliases: '-h',
-                 default: '0.0.0.0',
                  desc: 'Bind to HOST address'
     class_option :port,
                  aliases: '-p',
-                 default: '4567',
                  desc: 'The port Middleman will listen on'
     class_option :verbose,
                  type: :boolean,
@@ -40,7 +38,7 @@ module Middleman::Cli
     class_option :latency,
                  type: :numeric,
                  aliases: '-l',
-                 default: 0.25,
+                 default: 0.5,
                  desc: 'Set file watcher latency, in seconds'
 
     # Start the server
diff --git a/middleman-core/features/asset_hash.feature b/middleman-core/features/asset_hash.feature
index e64c9208..ea3b9d67 100644
--- a/middleman-core/features/asset_hash.feature
+++ b/middleman-core/features/asset_hash.feature
@@ -79,6 +79,13 @@ Feature: Assets get file hashes appended to them and references to them are upda
     And I should see 'images/100px-5fd6fb90.jpg'
     And I should see 'images/100px-1242c368.png'
 
+  Scenario: Hashed assets work with Slim
+    Given the Server is running at "asset-hash-app"
+    When I go to "/slim.html"
+    And I should see 'src="images/300px-59adce76.jpg"'
+    And I should see 'src="images/100px-5fd6fb90.jpg"'
+    And I should see 'srcset="images/100px-5fd6fb90.jpg 1x, images/200px-c11eb203.jpg 2x, images/300px-59adce76.jpg 3x"'
+
   Scenario: Enabling an asset host still produces hashed files and references
     Given the Server is running at "asset-hash-host-app"
     When I go to "/"
diff --git a/middleman-core/features/helpers_link_to.feature b/middleman-core/features/helpers_link_to.feature
index 18d0c497..90b6f08a 100644
--- a/middleman-core/features/helpers_link_to.feature
+++ b/middleman-core/features/helpers_link_to.feature
@@ -5,6 +5,24 @@ Feature: link_to helper
     When I go to "/link_to_erb.html"
     Then I should see "erb <s>with html tags</s>"
 
+  Scenario: link_to works with absolute URLs (where the relative part matches a local path)
+    Given a fixture app "link-to-app"
+    And a file named "config.rb" with:
+    """
+    set :relative_links, true
+    """
+    And a file named "source/test.html.erb" with:
+    """
+    Hello
+    """
+    And a file named "source/link_to_absolute.html.erb" with:
+    """
+    <%= link_to "test", "http://google.com/test.html" %>
+    """
+    And the Server is running at "link-to-app"
+    When I go to "/link_to_absolute.html"
+    Then I should see '<a href="http://google.com/test.html">test</a>'
+
   Scenario: link_to works with blocks (slim)
     Given the Server is running at "link-to-app"
     When I go to "/link_to_slim.html"
diff --git a/middleman-core/features/image_srcset_paths.feature b/middleman-core/features/image_srcset_paths.feature
new file mode 100644
index 00000000..b6b1046c
--- /dev/null
+++ b/middleman-core/features/image_srcset_paths.feature
@@ -0,0 +1,7 @@
+Feature: Support srcset property as params for image_tag helper
+  This lets you specify responsive image sizes
+
+  Scenario: Rendering an image with the feature enabled
+    Given the Server is running at "image-srcset-paths-app"
+    When I go to "/image-srcset-paths.html"
+    Then I should see '//example.com/remote-image.jpg 2x, /images/blank_3x.jpg 3x'
\ No newline at end of file
diff --git a/middleman-core/features/markdown_kramdown_in_haml.feature b/middleman-core/features/markdown_kramdown_in_haml.feature
index 5b5a5871..5980e1b7 100644
--- a/middleman-core/features/markdown_kramdown_in_haml.feature
+++ b/middleman-core/features/markdown_kramdown_in_haml.feature
@@ -33,9 +33,10 @@ Feature: Markdown support in Haml (Kramdown)
       :markdown
         [A link](/link_target.html)
 
-        ![image](blank.gif)
+        ![image](blank.gif){: srcset="image_2x.jpg 2x"}
       """
     Given the Server is running at "markdown-in-haml-app"
     When I go to "/link_and_image/"
     Then I should see "/link_target/"
+    Then I should see "/images/image_2x.jpg 2x"
     Then I should see 'src="/images/blank.gif"'
diff --git a/middleman-core/fixtures/asset-hash-app/source/slim.html.slim b/middleman-core/fixtures/asset-hash-app/source/slim.html.slim
new file mode 100644
index 00000000..dc74a5ee
--- /dev/null
+++ b/middleman-core/fixtures/asset-hash-app/source/slim.html.slim
@@ -0,0 +1,8 @@
+---
+directory_index: false
+layout: false
+---
+
+= image_tag '100px.jpg', srcset: "100px.jpg 1x, 200px.jpg 2x, 300px.jpg 3x"
+
+= image_tag "300px.jpg"
\ No newline at end of file
diff --git a/middleman-core/fixtures/image-srcset-paths-app/image-srcset-paths.html.erb b/middleman-core/fixtures/image-srcset-paths-app/image-srcset-paths.html.erb
new file mode 100755
index 00000000..b5fba613
--- /dev/null
+++ b/middleman-core/fixtures/image-srcset-paths-app/image-srcset-paths.html.erb
@@ -0,0 +1 @@
+<%= image_tag 'blank.jpg', srcset: '//example.com/remote-image.jpg 2x, blank_3x.jpg 3x, http://example.com/remoteimage.jpg 4x' %>
\ No newline at end of file
diff --git a/middleman-core/fixtures/image-srcset-paths-app/images/blank.gif b/middleman-core/fixtures/image-srcset-paths-app/images/blank.gif
new file mode 100755
index 00000000..2498f1aa
Binary files /dev/null and b/middleman-core/fixtures/image-srcset-paths-app/images/blank.gif differ
diff --git a/middleman-core/fixtures/large-build-app/config.rb b/middleman-core/fixtures/large-build-app/config.rb
index ae596127..590f9d7f 100644
--- a/middleman-core/fixtures/large-build-app/config.rb
+++ b/middleman-core/fixtures/large-build-app/config.rb
@@ -1 +1,3 @@
 page "/spaces in file.html", layout: false
+
+config[:port] = 5555
diff --git a/middleman-core/lib/middleman-core/application.rb b/middleman-core/lib/middleman-core/application.rb
index 210f2c16..02c2ef20 100644
--- a/middleman-core/lib/middleman-core/application.rb
+++ b/middleman-core/lib/middleman-core/application.rb
@@ -81,6 +81,14 @@ module Middleman
     define_hook :before_render
     define_hook :after_render
 
+    # Which host preview should start on.
+    # @return [Fixnum]
+    config.define_setting :host, '0.0.0.0', 'The preview server host'
+
+    # Which port preview should start on.
+    # @return [Fixnum]
+    config.define_setting :port, 4567, 'The preview server port'
+
     # Name of the source directory
     # @return [String]
     config.define_setting :source, 'source', 'Name of the source directory'
diff --git a/middleman-core/lib/middleman-core/cli/server.rb b/middleman-core/lib/middleman-core/cli/server.rb
new file mode 100644
index 00000000..cf3afafc
--- /dev/null
+++ b/middleman-core/lib/middleman-core/cli/server.rb
@@ -0,0 +1,86 @@
+# CLI Module
+module Middleman::Cli
+  # Server thor task
+  class Server < Thor
+    check_unknown_options!
+
+    namespace :server
+
+    desc 'server [options]', 'Start the preview server'
+    method_option :environment,
+                  aliases: '-e',
+                  default: ENV['MM_ENV'] || ENV['RACK_ENV'] || 'development',
+                  desc: 'The environment Middleman will run under'
+    method_option :host,
+                  type: :string,
+                  aliases: '-h',
+                  desc: 'Bind to HOST address'
+    method_option :port,
+                  aliases: '-p',
+                  desc: 'The port Middleman will listen on'
+    method_option :verbose,
+                  type: :boolean,
+                  default: false,
+                  desc: 'Print debug messages'
+    method_option :instrument,
+                  type: :string,
+                  default: false,
+                  desc: 'Print instrument messages'
+    method_option :disable_watcher,
+                  type: :boolean,
+                  default: false,
+                  desc: 'Disable the file change and delete watcher process'
+    method_option :profile,
+                  type: :boolean,
+                  default: false,
+                  desc: 'Generate profiling report for server startup'
+    method_option :reload_paths,
+                  type: :string,
+                  default: false,
+                  desc: 'Additional paths to auto-reload when files change'
+    method_option :force_polling,
+                  type: :boolean,
+                  default: false,
+                  desc: 'Force file watcher into polling mode'
+    method_option :latency,
+                  type: :numeric,
+                  aliases: '-l',
+                  default: 0.25,
+                  desc: 'Set file watcher latency, in seconds'
+
+    # Start the server
+    def server
+      require 'middleman-core'
+      require 'middleman-core/preview_server'
+
+      unless ENV['MM_ROOT']
+        puts '== Could not find a Middleman project config.rb'
+        puts '== Treating directory as a static site to be served'
+        ENV['MM_ROOT'] = Dir.pwd
+        ENV['MM_SOURCE'] = ''
+      end
+
+      params = {
+        port: options['port'],
+        host: options['host'],
+        environment: options['environment'],
+        debug: options['verbose'],
+        instrumenting: options['instrument'],
+        disable_watcher: options['disable_watcher'],
+        reload_paths: options['reload_paths'],
+        force_polling: options['force_polling'],
+        latency: options['latency']
+      }
+
+      puts '== The Middleman is loading'
+      ::Middleman::PreviewServer.start(params)
+    end
+  end
+
+  def self.exit_on_failure?
+    true
+  end
+
+  # Map "s" to "server"
+  Base.map('s' => 'server')
+end
diff --git a/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb b/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
index 95801c20..e66c1739 100644
--- a/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/default_helpers.rb
@@ -221,5 +221,26 @@ class Middleman::CoreExtensions::DefaultHelpers < ::Middleman::Extension
       url = url_for(url, options)
       super
     end
+    
+    # Modified Padrino image_tag so that it finds the paths for srcset
+    # using asset_path for the images listed in the srcset param
+    def image_tag(path, params={})
+      params.symbolize_keys!
+      
+      if params.key?(:srcset)
+        images_sources = params[:srcset].split(',').map do |src_def|
+          if src_def.include?('//')
+            src_def
+          else
+            image_def, size_def = src_def.strip.split(/\s+/)
+            asset_path(:images, image_def) + ' ' + size_def
+          end
+        end
+
+        params[:srcset] = images_sources.join(', ')
+      end
+
+      super(path, params)
+    end
   end
 end
diff --git a/middleman-core/lib/middleman-core/preview_server.rb b/middleman-core/lib/middleman-core/preview_server.rb
index 0514c58b..e89e552f 100644
--- a/middleman-core/lib/middleman-core/preview_server.rb
+++ b/middleman-core/lib/middleman-core/preview_server.rb
@@ -6,8 +6,6 @@ require 'middleman-core/rack'
 # rubocop:disable GlobalVars
 module Middleman
   module PreviewServer
-    DEFAULT_PORT = 4567
-
     class << self
       extend Forwardable
 
@@ -17,9 +15,7 @@ module Middleman
       # Start an instance of Middleman::Application
       # @return [void]
       def start(opts={})
-        @options = opts.dup.freeze
-        @host = @options[:host] || '0.0.0.0'
-        @port = @options[:port] || DEFAULT_PORT
+        @options = opts
 
         mount_instance(new_app)
         logger.info "== The Middleman is standing watch at #{uri}"
@@ -90,7 +86,7 @@ module Middleman
       private
 
       def new_app
-        opts = @options
+        opts = @options.dup
 
         ::Middleman::Logger.singleton(
           opts[:debug] ? 0 : 1,
@@ -103,6 +99,9 @@ module Middleman
           config[:watcher_force_polling] = opts[:force_polling]
           config[:watcher_latency] = opts[:latency]
 
+          config[:host] = opts[:host] if opts[:host]
+          config[:port] = opts[:port] if opts[:port]
+
           ready do
             match_against = [
               %r{^config\.rb$},
@@ -118,6 +117,9 @@ module Middleman
           end
         end
 
+        @host = app.config[:host]
+        @port = app.config[:port]
+
         app.files.on_change :reload do
           $mm_reload = true
           @webrick.stop
diff --git a/middleman-core/lib/middleman-core/sources/source_watcher.rb b/middleman-core/lib/middleman-core/sources/source_watcher.rb
index 6722727f..d2bbbe92 100644
--- a/middleman-core/lib/middleman-core/sources/source_watcher.rb
+++ b/middleman-core/lib/middleman-core/sources/source_watcher.rb
@@ -128,7 +128,11 @@ module Middleman
     def listen!
       return if @disable_watcher || @listener || @waiting_for_existence
 
-      config = { force_polling: @force_polling }
+      config = {
+        force_polling: @force_polling,
+        wait_for_delay: 0.5
+      }
+
       config[:latency] = @latency if @latency
 
       @listener = ::Listen.to(@directory.to_s, config, &method(:on_listener_change))
diff --git a/middleman-core/lib/middleman-core/util.rb b/middleman-core/lib/middleman-core/util.rb
index 945c4f96..debde48e 100644
--- a/middleman-core/lib/middleman-core/util.rb
+++ b/middleman-core/lib/middleman-core/util.rb
@@ -283,7 +283,7 @@ module Middleman
       if path_or_resource.is_a?(::Middleman::Sitemap::Resource)
         resource = path_or_resource
         resource_url = url
-      elsif this_resource && uri.path
+      elsif this_resource && uri.path && !uri.host
         # Handle relative urls
         url_path = Pathname(uri.path)
         current_source_dir = Pathname('/' + this_resource.path).dirname
@@ -299,7 +299,7 @@ module Middleman
           resource = app.sitemap.find_resource_by_destination_path(url_path.to_s)
           resource_url = resource.url if resource
         end
-      elsif options[:find_resource] && uri.path
+      elsif options[:find_resource] && uri.path && !uri.host
         resource = app.sitemap.find_resource_by_path(uri.path)
         resource_url = resource.url if resource
       end
diff --git a/middleman-core/lib/middleman/rack.rb b/middleman-core/lib/middleman/rack.rb
index 6fbd2129..51ddb4c4 100644
--- a/middleman-core/lib/middleman/rack.rb
+++ b/middleman-core/lib/middleman/rack.rb
@@ -2,3 +2,4 @@ require 'middleman-core/load_paths'
 ::Middleman.setup_load_paths
 
 require 'middleman-core'
+require 'middleman-core/application'